化简2x2﹣（x2﹣3x）﹣2x
解:
原式=2x2﹣x2+3x﹣2x=x2+x
做一节圆柱形通风管需多少铁皮，是求通风管的（ ）
A．侧面积
B．表面积
C．体积
D．容积
—_______.
—It was October 9th. [ ]
A. What was the date yesterday?
B. What day was it yesterday?
C. What time was it?
D. How far was it?
